Hello, Paulatto, thank you for your suggestion. I got reasonable phonon frequencies by using LO-TO splitting, wow!!!! I'm very happy to solve problem, thanks again, Atsushi
2019年4月26日(金) 19:03 Lorenzo Paulatto <[email protected]>: > Hello, did you try to set a direction for the LO-TO splitting in the > dynmat input? > Kind regards > > -- > Lorenzo Paulatto > > On Fri, 26 Apr 2019, 10:16 Atsushi Yamada, <[email protected]> wrote: > >> Hi, >> >> I'm beginner of QE (just I started to use it from a week ago) and I'm >> facing a problem that my calculations do not reproduce correct phonon >> frequencies. My material is 4H-SiC which is popular and well studied. I >> want to reproduce phonon frequencies at gamma point shown in Fig.2(b) of >> the following paper: >> https://arxiv.org/pdf/1705.02634.pdf >> >> It tells that the phonon dispersion in the figure is calculated by >> Quantum Espresso v 5.4.0 and calculation conditions are given. I calculated >> with the same conditions, but the high phonon frequencies region are not >> good agreement. I tried many calculations with various options and >> parameters, but I couldn't get good agreement, and now, I have no idea to >> solve it. My resultant frequencies at the gamma point are: >> >> # mode [cm-1] [THz] IR >> 1 -0.00 -0.0000 0.0000 >> 2 -0.00 -0.0000 0.0000 >> 3 0.00 0.0000 0.0000 >> 4 192.54 5.7721 0.0000 >> 5 192.54 5.7721 0.0000 >> 6 200.76 6.0186 0.0000 >> 7 200.76 6.0186 0.0000 >> 8 259.89 7.7914 0.0015 >> 9 259.89 7.7914 0.0015 >> 10 404.77 12.1347 0.0000 >> 11 412.80 12.3755 0.0000 >> 12 613.53 18.3931 0.1675 >> 13 785.34 23.5439 0.0320 >> 14 785.34 23.5439 0.0320 >> 15 793.13 23.7774 0.0000 >> 16 793.13 23.7774 0.0000 >> 17 795.96 23.8622 85.2162 >> 18 801.09 24.0162 0.0000 >> 19 801.09 24.0162 0.0000 >> 20 811.70 24.3343 80.2329 >> 21 811.70 24.3343 80.2329 >> 22 851.64 25.5315 0.3206 >> 23 926.17 27.7658 0.0000 >> 24 935.31 28.0398 0.0000 >> >> Especially, modes 20-24 are obviously different from the paper (and other >> literature): The paper is like, (probably) frequencies of the modes 22 and >> 23 are close (but my result is not like that) and modes 20 and 21 are not >> degenerated (but my result shows degeneracy). The results of my >> calculations did not change if I use other options, thresholds and >> pseudopotential. >> Maybe relating to this problem, my cell size obtained by geometry >> optimization is not the same to the values shown in the paper (3.07A, >> 10.05A in Table 1 of the paper). >> >> My input files and calculations are as followings: >> (now, I used latest version of QE, 6.4.1, but result by QE 5.4 was the >> same) >> >> (1) geometry optimization: >> pw.x -in ./SiC.opt.in > ./SiC.opt.out >> (2) SCF calculation: >> pw.x -in ./SiC.scf.in > ./SiC.scf.out >> (3) Phonon calculation >> ph.x -in ./SiC.phG.in > ./SiC.phG.out >> (4) Dynamical matrix calculation >> dynmat.x < SiC.dynmat.in > SiC.dynmat.out >> >> Input files: >> [1] SiC.opt.in >> &control >> calculation='vc-relax' >> prefix='SiC', >> pseudo_dir = './pseudo/', >> outdir='./tmp/' >> etot_conv_thr=1d-7 >> forc_conv_thr=1d-7 >> / >> &system >> ibrav= 4, >> A= 3.0760, >> C= 10.0400, >> nat= 8, >> ntyp= 2, >> ecutwfc = 60.0, >> ecutrho =240 >> / >> &electrons >> conv_thr = 1.0d-10 >> / >> &ions >> ion_dynamics='bfgs' >> / >> &cell >> cell_dofree='ibrav' >> / >> ATOMIC_SPECIES >> Si 28.086 Si.pz-n-nc.UPF >> C 12.0107 C.pz-nc.UPF >> ATOMIC_POSITIONS angstrom >> Si 0.00000000 1.77592943 2.51000000 >> C 0.00000000 1.77592943 4.39250000 >> Si 0.00000000 0.00000000 0.00000000 >> C 0.00000000 0.00000000 1.88250000 >> Si 1.53800000 0.88796471 7.53000000 >> C 1.53800000 0.88796471 9.41250000 >> Si 0.00000000 0.00000000 5.02000000 >> C 0.00000000 0.00000000 6.90250000 >> K_POINTS automatic >> 8 8 4 0 0 0 >> ------------------------ >> >> [2] SiC.scf.in >> &control >> calculation='scf' >> prefix='SiC', >> pseudo_dir = './pseudo/', >> outdir='./tmp/' >> / >> &system >> ibrav= 4, >> A= 3.04337366, !<-- obtained from the optimization >> C= 9.96163727, !<-- obtained from the optimization >> nat= 8, >> ntyp= 2, >> ecutwfc = 60.0, >> ecutrho =240 >> / >> &electrons >> conv_thr = 1.0d-10 >> / >> ATOMIC_SPECIES >> Si 28.086 Si.pz-n-nc.UPF >> C 12.0107 C.pz-nc.UPF >> ATOMIC_POSITIONS angstrom >> Si 0.000000000 1.757092472 2.489491419 >> C 0.000000000 1.757092472 4.362543288 >> Si 0.000000000 -0.000000000 -0.001538102 >> C -0.000000000 -0.000000000 1.865935344 >> Si 1.521686716 0.878546231 7.470309676 >> C 1.521686716 0.878546231 9.343361545 >> Si -0.000000000 0.000000000 4.979280155 >> C -0.000000000 0.000000000 6.846753601 >> K_POINTS automatic >> 8 8 4 0 0 0 >> ------------------------- >> >> [3] SiC.phG.in >> Phonons of SiC at Gamma >> &inputph >> tr2_ph=1.0d-16, >> prefix='SiC', >> outdir='./tmp' >> fildyn='SiC.dynG', >> epsil=.true. >> / >> 0.0 0.0 0.0 >> ------------------------- >> >> [4] SiC.dynmat.in >> &input >> fildyn='SiC.dynG', >> asr='simple' >> / >> ------------------------ >> >> What is wrong...? >> I'm so glad if you kindly help me. >> >> best, >> Atsushi Yamada >> >> >> _______________________________________________ >> Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso) >> users mailing list [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users -- __/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/ Atsushi Yamada University of Tsukuba Center for Computational Sciences __/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/__/
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